The invention relates to an electronic door lock for an electronic key provided with an electronic store for a key word datum, with a latch bolt engaging in a keep plate and actuatable at least from the inner side of the door by means of a handle, a bolt movable out to lock in the keep plate, an electronically controllable locking mechanism for the bolt, a reading device for the key word datum of the electronic key and a control circuit controlling the locking mechanism in dependence upon the read key word datum.
A door lock of this kind is known. In the conventional manner it comprises a latch bolt which is opened from the inner side of the door by means of a handle. The bolt of the door lock is closable, similarly to a cylinder lock, by means of a twist knob from the inner side of the door. In place of a lock cylinder lockable from the outside of the door by means of a mechanical key, a twist knob is likewise provided on the outside of the door and is couplable with the internal twist knob through an electrically controllable coupling. The normally freely rotatable outer twist knob, when the coupling is engaged, permits manual actuation both of the bolt and of the latch bolt. The coupling is controlled by a control circuit in dependence upon the key word datum of an electronic key which can be read by way of a reading device of the lock. The known electronic lock differs as regards its operation from conventional mechanical locks since it must first be set with the electronic key into locking readiness and then locked by means of its twist knob.
Another known electronic door lock is based upon a conventional cylinder lock. It has a lock cylinder through which both the bolt and the latch bolt can be actuated by means of an inserted key. The lock cylinder is couplable through an electrically controllable coupling with the actuating mechanism of the lock and contains a reading device for the key word information stored in a store of the electronic key. A control circuit controls the coupling in dependence upon the read key word datum. From the outside of the door the lock is additionally overlockable by a mechanical key, so that it may be opened even in emergencies. In this known door lock the key, as usual in conventional door locks, must be turned through a comparatively large angle of rotation for the actuation of the bolt and the latch bolt. This is frequently felt to be uncomfortable, for example if the key is hanging together with a plurality of other keys on a key holder.